Duchowny 1999.

Methods	Randomized, double blind, parallel group, multi‐centre study. Two treatment arms: 1 placebo, 1 lamotrigine. Pre‐randomization baseline period = 8 weeks. Treatment phase = 18 weeks (including 6‐week titration). Taper and follow‐up = 1 to 6 weeks, including 1‐week taper.
Participants	40 centres from USA and France: 199 children with refractory drug‐resistant partial seizures, aged from 2 to 16 years (27% were less than 6 years old, 60% aged between 6 to 12 years and 11% were over 12 years age). 98 were allocated to lamotrigine and 101 to placebo. There were 103 boys and 96 girls. Maximum number of other AEDs = 2.
Interventions	Add‐on lamotrigine or placebo. Median dose ranged from 2.7 to 12.9 mg/kg/day depending upon concurrent use of other AEDs. Participants on valproate received lower doses.
Outcomes	(1) 50% responder rates. (2) Withdrawal from study for any reason. (3) Adverse effects.
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Computer‐generated random permuted blocks.
Allocation concealment (selection bias)	Low risk	Patients were randomised with a blocked randomisation scheme to treatment with add‐on lamotrigine or matched placebo in bottles labelled with pre‐generated participant numbers.
Blinding (performance bias and detection bias) All outcomes	Low risk	Treatment assignments were unknown to all study‐site personnel, patients and sponsors. Lamotrigine and matching placebo were provided as berry‐flavoured, chewable, dispersible caplets or tablets in strengths of 5, 25, and 100 mg.
Incomplete outcome data (attrition bias)	Low risk	No participants were excluded from analysis. 2 enrolled participants withdrew before randomisation. 14 participants allocated to lamotrigine and 18 participants allocated to placebo withdrew during treatment phase. The reasons for exclusion were reported.
Selective reporting (reporting bias)	Low risk	All outcomes stated in methods section of paper were reported in the results. There was no protocol available to check a priori outcomes.
Other bias	Unclear risk	This study was sponsored by GlaxoSmithKline, the manufactures of LTG.